Whether produced by LED monochrome, color or tri-color screen, the image needs to be displayed constitute emission brightness of each LED pixel must be able to adjust p4led full color, its adjustable sophistication that the gray levels. The higher gradation, image display more delicate, color is also more abundant, the corresponding display control system is also more complex. General 256 full-color gray-scale images, color transition has been very soft, and 16 gray-scale color images, color transition boundaries are clear. So indoor full color, color LED screen requirements are currently made 256-4096 gray. Led unit board problems are divided into four points: 1, the entire board is not shining: mainly because of the power unit board or board within a missed line connection error p8 full-color, resulting in a difference of positive and negative circuits. 2, the board is not shining, transportation function properly: this is due to damage caused by the built-in circuit board can be 74HC138 4 feet and 5 feet caused by short circuit. 3, every three non-shiny: In 4953 the board is damaged. 4, interlaced shiny: to be able to analyze a circuit problem. ①: Check the cell plate Built 74HC245 and 74HC138 whether Weld. ②: use a multimeter to measure whether the 74HC138 1 pin voltage is about 2.5V, there will replace 74HC138③: measuring electricity transmission status lilies with ICA signals. p4led full color, Yasuhiro photovoltaic (certified), full color provided by Linyi Wang Tai Electronics Limited. Linyi Wang Tai Electronics Co., Ltd. (www.ledzkd.com) (www.ledzkd.com) is a leader in Linyi, display devices, over the years, the company is implementing the scientific management, innovation and development, the principle of honesty and trustworthiness, and satisfy customers needs. In Hong Thai Optical leadership with the staff warmly welcome all inquiries negotiations to create the Thai macro photoelectric a better future.